Giant Veggie Rosti Topped with Eggs

• 400 g potatoes, grated
• 0.5 brown onion, grated
• 300 g sweet potato, grated
• 2 tsp cumin
• 3 tbsp extra virgin olive oil
• 1 tsp seeded mustard
• 0.5 lemon, squeezed
• 2 cup baby spinach
• 0.5 cup frozen green peas, thawed
• 4 eggs
• 2 tbsp white vinegar
• 100 g danish feta, crumbled